Ferroelectric anomaly of perovskite layer structured Pb<sup>2+</sup>-doped Sr<inf>2</inf>Nb<inf>2</inf>O<inf>7</inf> ceramics
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DOI
10.1111/jace.19669
Journal
Journal of the American Ceramic Society
ISSN
0002-7820
Metadata
Show full item recordAbstract
The spontaneous polarization of perovskite layer structured Sr2Nb2O7 ferroelectrics (FEs) is originated from mainly the oxygen octahedral rotations and partially the displacement of Sr2+ ions. However, there is FE anomaly of showing the typical characteristics of antiferroelectric (AFE)-like behavior with double polarization–electric field hysteresis loops of Sr2Nb2O7 ceramics by Pb doping. Here, combinations of low frequency and sub-terahertz band dielectric measurements under applied DC field reveal field-induced transition from AFE to FE structure. Temperature dependence of dielectric constant suggested a second-order phase transition near 215°C, which further supported by the lattice parameters and thermal expansion coefficient extracted from the variable temperature X-ray diffraction in the heating and cooling processes. The selected area electron diffraction results show no new superlattice spots are observed along [1 0 0] zone axis related to c direction. We proposed a model based on octahedral tilting/rotation that accounted for the incommensurate lattice modulation in the c direction for Sr2Nb2O7 system by Pb doping. All the results show AFE-like behavior be likely to origin from the electron structures of Pb2+ with a 6s2 lone pair. Our results gave us a new concept provide possibilities for the design of AFE-like materials in layer structured compounds with super high FE Curie point.
Authors
Liu, L; Chen, T; Ouyang, D; Yue, Y; Yang, B; Yan, H; Abrahams, I; Fu, Z; Liang, R; Zhou, ZCollections
- Awaiting Allocation [572]